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Bloom Energy Claims a New Fuel Cell Technology

Two 100-kilowatt Bloom Energy Servers, as the company calls them, at a site in California. Credit
Bloom Energy

SUNNYVALE, Calif. — A Silicon Valley company is claiming a breakthrough in a decades-old quest to develop fuel cells that can supply affordable and relatively clean electricity. Google, Bank of America, Wal-Mart and other large corporations have been testing the devices, which will be formally introduced on Wednesday.

The start-up, Bloom Energy, has raised about $400 million from investors and spent nearly a decade developing a new variety of solid oxide fuel cell, considered the most efficient but most technologically challenging fuel-cell technology.

K. R. Sridhar, Bloom’s co-founder and chief executive, said devices made by his company were generating electricity at a cost of 8 to 10 cents a kilowatt hour, using natural gas. That is lower than commercial electricity prices in some parts of the country.

“We got into this business to make affordable electricity, not fuel cells,” Mr. Sridhar said Tuesday as workers assembled stacks of fuel cells in tall, round cylinders and installed them in silver metal cubes at Bloom’s headquarters in a Silicon Valley office park.

The company has been working on the technology for eight years while saying little. The secrecy, and the prominence of the venture capitalists backing Bloom, have fueled both hype and skepticism about its efforts. Bloom is scheduled to unveil the technology Wednesday at a news conference attended by Gov. Arnold Schwarzenegger of California and Colin Powell, the former secretary of state and a member of Bloom’s board.

While Bloom may well have created one of the most efficient fuel cells, it is unclear how widely the company’s technology will be adopted. Cost and durability have limited the use of other types of fuel cells, and it could be years before the potential of the company’s approach is clear.

“We have been working with solid oxide for 30 years but are still in the lab,” said Mike Brown, an executive with UTC Power, a division of the United Technologies Corporation and a leading fuel-cell maker. “Nobody has been able to resolve the reliability problem.”

Fuel cells, which convert hydrogen, natural gas or another fuel into electricity through an electrochemical process, have long held out the promise of cheap and plentiful energy while emitting fewer pollutants than conventional power plants. But the need to use expensive precious metals like platinum and rare earth elements in some fuel cells, and corrosive materials in others, has kept costs high and shortened their longevity.

Bloom claims it has learned to make the devices from common materials that will last for years. The Bloom fuel cell’s heart is a thin white ceramic wafer made from sand. At Bloom’s offices, Mr. Sridhar, a former NASA scientist, picked up a stack of fuel cells that resembled floppy disks. One side of each was painted with a lime-green ink that acts as the anode while a black ink on the back served as the cathode. Bloom executives would not disclose the composition of the ink.

Small cells are stacked to make a larger device. As natural gas or another fuel passes over the cell and mixes with oxygen from the air, a chemical reaction generates electricity.

Bloom executives contend that their device could cut the greenhouse gas emissions from electricity generation by at least 50 percent, depending on the type of fuel used — a claim that is likely to receive close scrutiny.

Mr. Brown, the UTC Power executive, said one of the biggest hurdles to developing solid oxide fuel cells has been engineering the stack to withstand extreme temperatures without cracking or leaking. “What is the durability of cell stack, how long will they operate before you have to pull them out and replace them and what is the cost to do that?” he said.

Mr. Sridhar contends the Bloom boxes, with reasonable maintenance, will have a 10-year life span.

“It’s a disruptive technology,” said John Doerr, a prominent venture capitalist who helped finance Bloom and sits on its board. “It works, so the hurdles are scale and cost. We’ve got to make a lot of these systems reliably, and that’s hard work.”

A version of this article appears in print on February 24, 2010, on page B5 of the New York edition with the headline: Start-Up Asserts Its Fuel Cell Can Lower Cost of Electricity. Order Reprints|Today's Paper|Subscribe